Robert j



R. J. PARSONS.

RESISTANCE UNIT.

APPLICATION mm was no. me.

Patented Sept. 9,1919.

Inventor Robert J. Par's ons,

by Hisaqt. or-ne UNITED STATES PATENT OFFICE. 1

ROBERT J. PARSONS, OF FORT WAYNE, INDIANA, ASSIGNOB TO GENERAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

RESISTANCE UNIT.

Specification of Letters Patent.

Patented Sept. 9, 1919.

Application filed June 10, 1918. Serial No. 289,117.

To all whom it may concern:

Be it known that I, Ronnn'r J. PARSONS, a citizen of the United States, residing at Fort Wayne, in the county of Allen, State of Indiana, have invented certain new and useful Improvements in Resistance Units, of which the following is a specification.

The present invention relates to resistance units and particularly a unit adapted for use in connection with controllers for regulating electric motors or generators, although it is not necessarily limited thereto.

One object of the invention is to provide an improved resistance unit which is simple and compact in structure, which can be readily assembled, and from which leads can be taken off at any point along its length.

A. further object of the invention is to provide an improved resistance unit in which the resistance element can be easily replaced when found desirable, and which although compact is sufliciently open for ventilating so that the resistance unitwill be properly cooled.

For a consideration of what I believe to be novel and my invention, attention is directed to the accompanying description and the claims appended thereto.

In the drawing, Figure 1 is a perspective view of a resistance unit embodying my invention; Fig. 2 is an end view thereof; Fig. 3 is a sectional view taken on line 33, Fig. 1; Figs. 4 and 5 are views of a connector, and

,Fig. 6 is a sectional view through a terminal support and a terminal fastened thereon.

Referring to the drawing, 5 indicates a resistance element in the form of a flat rib-- bon wound edgewise to form a helix. It is carried by two insulators 6 and 7 located inside the helix and held in spaced relation to each other by a support comprising two overlapping strips 8 and 9 provided with flanges 10 and 11 which engage the inner surfaces of the insulators. The insulators 6 and 7 are preferably made up in sections of suitable length and the two end sections of the insulator 6 are provided with enlarged heads 12 so that there is one of these heads at each end of the support 6. The outer surfaces of the insulators 6 and 7 are provided with projections 13 which serve to position and space a art the coils of the resistance element 5. he overlapping strips 8 and 9 are fastened together by short screws 14 which extend through oblong openings 15 in the strips 8 and 9. The two ends 5 of the resistance element 5 terminate adjacent the two heads 12, and they are held between pairs of clamping plates 16 which are fas tened together by bolts 16, one ofsuch bolts serving also to fasten the clamping plates and terminals to heads 12. In strip 8 there are holes 17 which overlap similar holes in the opposite strip 9. This is to afford means of spreading the two strips by driving wedges through the holes. After screws 14 are tightened the wedges are withdrawn. Openings 17 also serve to provide for ventilation.

The structure so far described is complete in itself and may be termed the resistance coil unit. It may be assembled by taking a resistance element 5 which has been wound edgewise into a helix, inserting insulators 6 and 7 into it to their approximate position, then inserting between the insulators, strips 8 and 9 which may have the screws 14-. loosely fastened into openings 15. Owing to the oblon openings 15, the strips 8 and 9 may he pus ed together sufiicientl to permit them to be readily slipped on wise between the insulators 6 and 7 after which the strips 8 and 9 are spread apart to bring the insulators 6 and 7 firmly into on agement with the turns of the resistance e ement 5. The screws 14 are then screwed up tight to hold the various parts in position. This forms in substance an adjustable Ibeam support for the insulators. The ends of flanges 10 and 11 are preferabl provided with short projections 18 which are bent against the ends of the insulators 6 and 7 to hold them from endwise movement relative to strips 8 and 9.

The resistance coil unit as above described is carried in a frame work comprising two U-shaped end frames 20 connected to each other at their bases by a strip 21. The two arms of the U-shaped and frames are connected together by mounting plates 22 by means of which the resistance unit may be mounted on any suitable base. One of the legs of each U-shaped member is provided with a turned-down extension 23 forming two hangers to which are fastened a terminal support 24 by means of bolts 24". Terminal support 24: may be made from sheet steel or other suitable material. The terminal support 24 together with the strip 21 serves to hold the U-shaped end frames 20 in spaced relation to each other and to build up a frame work for the resistance unit. The resistance coil unit is mounted in the end frames by means of bolts 25, one or hot of the stri s 8 and 9 being extended beyond the end oi the insulators 6 and 7 to receive these bolts. On the bolts are suitable spacing sleeves 26 which serve to center the resistance coil unit. Located between each pair of clamping plates 16 is a terminal connecting strip 27 which is suitably bent to extend down in front of the terminal support 24. It is connected to the terminal support by a bolt 28', the connecting strip 27 and bolt 28 being suitably insulated from the terminal support 24 by insulating member 28* as shown in Fig. 6. 29 is a conhector to which a lead wire can be soldered or otherwise fastened. 7

To tap o'fl' connections at desired points along the resistance element 5 l utilize a flat slotted connecting clamp 30 having a threaded shank 31 as shown in Figs. 4 and 5. The clamp 30 is slipped over the re sistance element 5 at any desired point so that such element rests in the bottom of theslot therein. A eonnectin strip 32 is then inserted in the slot above t e resistance element 5 and a nut 33 screwed over the head 31. This firmly connects these part together. terminal support 24 to bring it in front of said support and is connected to it after the manner illustrated in Fig. 6 in connection with strip 27. In the present instance fo'ur intermediate taps are shown but it will be understood of course, that as many of these may be utilized as found desirable.

The resistance coil unit can be readily mounted in the frame work by inserting it into the same and putting the bolts 25 into place, after which the clamps 30 and connecting strips 27 and 32 can be arran ed in position. In case it becomes desire 10 to replace the resistance element 5, the clamps 30 can be unfastened and bolts 25 re- The strip 32 is bent around the moved permitting the resistance coil unit as a whole to be removed from the frame. A new one can then be inserted in its place or the old one can be repaired and reiir serted. In any event it is a comparatively siinple matter and none oi? the soldered connections on the terminal support 2% need be disturbed.

In accordance with the provisions of the patent statutes, l have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is r 1. In a resistance unit, a resistance element comprising a pair of spaced insulators, adjustable means for holding them in spaced relation, and a resistor wound on said insulators to form a helix; a frame comprising U-shaped end pieces each having one leg provided with a turned-down extension, and means supporting said end pieces in spaced relation to each other; means detachably connecting said resistance element to said frame, a terminal support carried by said extension, and connections leading from turns of said resistor to said terminal sup port.

2. In a resistance unit, a resistance element comprising a pair of spaced insulators havin a resistor wound thereon, U-shaped end pieces adapted to be mounted in spaced relation to each other, means fastening said resistance element to said U-shaped end pieces with the ends of the element between the legs of said U-shaped end pieces, a terminal support carried by said U-shaped end pieces, and connections leading from said resistor to said terminal support.

In witness whereof, I have hereunto set my hand this 6th day of June, 1918.

ROBERT J PARSONS.

Copies of this patent may be mama for me cents each, by addressing the Gozhmtsaioner of Patents, waihington, D. G. 

